Spark plug



Aug. 7, 1928. 1,679,988

H. RABEZZANA SPARK PLUG Filed March 1, 1926 Patented Aug. 7, 1928.

UNITED STATES HECTOR RAJBEZZANA, OF FLINT,

SPARK Application filed March 1,

The invention relates to a spark plug, and more particularly to improvements in the method of securln the side electrode wire to the shell thereo One of the objects of my invention is to provide a practical, simple and inexpens ve means of expanding an electrode wire mside an aperture in the wall of the shell.

Other objects will appear hereinafter.

The invention consists in the novel ar-- rangement and construction of parts more particularly described in the following specification and pointed out in the annexed claims. 4

In the accompanying drawing:

Figure 1 is a diagrammatical view showing, partly in section, an elevation of a vspark plug, and illustrating the method of fastening a side electrode wire inside the shell thereof.

Figure 2 is a view similar to Flgure 1, showing an abbreviated form of side electrode, and the use of a pair of pivoted gripping jaws.

Figure 3 is a similar view showing a modified form of the side electrode, and a -pair of jaws formed with a relatively deep gripping surface.

Figure 4 is a part sectional, elevational view of the plug shown in Figure 2 in finished form.

Like numerals of reference indicate similar parts in the different figures. In Figure 1, the spark plug 5 has its wall formed 0 with diametrically disposed inwardly tapering apertures 6. A side electrode 7, consisting, in this instance, of a continuous wire extending across the plug, is expanded, or wedged, inside the tapered apertures 6.

To accomplish this purpose, I have provided an implement connected with an electrical current and comprising a gripping body portion 9, carrying at one end a fiat metallic shoe or cap 10, which forms one side of a transformer line, as indicate in the drawing. A control switch 11 is provided. The implement 8 is brought against one end of the electrode, the other end being received by asuitable stationary object 12 as shown in Figure 1. The switch 11 is then closed and a firm momentary ressure is applied. The side electrode wire 7 is made to assume an intermediate metallic union with the wall of the spark plug. The electrical current and pressure causes the MICHIGAN, ASSIGNOR TO A C SPARK PLUG COMPANY, OF FLINT, MICHIGAN.

PLUG.

1926. Serial No. 91,487.

wire to expand or swell until it fits tightly,

at which point the operation becomes completed. It will be obvious that if the operation would continue over a longer period, a welding between the parts would be effected, which I aim to obviate. The electrode wire in spark plugs of this type is usually of nickel or some alloy thereof which is of lower melting point than the material of the spark plug wall or shell, which is ordinarily steel.

It will be understood that the above described means of fastening the side electrode wire 7 in place, falls short of a weld, and is, in substance, a mere forced fit.

In lieu of the implement 9, a pair of recessed jaws 13 (see Figure 2) may be used. In Figure 3, I have shown the said recessed jaws formed with a more extensive recess by which the electrode wire may be engaged. The jaws 13 preferably constitute onecxtremit of-a pair of insulated pincers (not shown{ connected to an electrical circuit in a similar manner as disclosed in Figure 1.

Qbviously, the said jaws may be either long or short, but it will be evident that by having lon er jaws (as shown in Figure 3), the electro e wire 7 is more completely surrounded, and,'ofcourse, the heating of the electrode is effected in a comparatively shorter time.

In Figure 2, a member 14 is inserted within the plug to properly position the said electrode wire during the expanding operation. In this instance, since the wire does not extend wholly across the plug an important econom in material and operation, obviously, is e ected. In Figure 3, a vertically drilled aperture, having a diameter somewhat greater than the electrode wire 7, is utilizedrather than the tapered aperture of Figures 1 and 2.

It will be understood that any surplus material remaining after 1 the above ded scribed operation, may readily be removed 1. A spark plug including an electrode wire, a bottom wall provided with orifices operation, the said wire being connected to" I the wall of the spark plug in an intermediate union less than a weld.

2. A spark plug including a wall formed with a tapered orifice, an electrode extended therethrough, and having an expanded portion conforming to the shape of the said orifice.

3. A spark plug including a wall formed with two oppositely disposed tapered orifices, an electrode running across the said plug and having its ends expanded in a forced fit to conform to the interior of the said orifices.

4. The combination in a spark plug of a metallic shell and a metallic electrode wire, the shell having a recess of larger diameter than the said wire, one end of said electrode being positioned within said recess and expanded therein to fit the recess, thereby supporting the electrode and providing electric conducting contact between the electrode and the shell.

5; The method of securing a spark plugelectrode to a spark plug shell comprising providing in the shell a recess of greater diameter than the electrode, positioning a portion of the electrode in said recess, engaging the portion of theelectrode which proJects from the recess with a tool adapted to supply heating current tosaid electrode, and applying heating current and pressure to said electrode by means of said tool thereby expanding the portion Within the recess.

In testimony whereof I afiix my signature.

HECTOR RABEZZANA. 

